Rack for holding master sheets



y 8, 1952 F. H. DAVIS 2,602,395

RACK FOR HOLDING MASTER SHEETS Filed Dec. 27, 1949 INVENTOR. FRED H. DA v/s W50 9 zlfgs,

Patented July 8, 1952 UNITE-D STATES OFFICE I Application-December 2'7, 1949Serial No. 135,288

inventionzrelates-zto =a "rackrfor'holding-an oifsetnnasterssheet :or e the like during -1 treatment .ofithcnnaster :sheet'; in acleaning, .;preserving, :and developing athe master-sheet and inv other treatmentzthereof.

.iInzone type:oinfisetprintins, copy isset up on :afflexible :mas-ter *sheet. The copy is inked anditherink gis-transierredtman offset .roll which does-the :actual :printing. 1 Master :sheets, "which maybe madegofthin-rfiexiblmsheet materialzsuch as zinc, :aluminum, aipaper, .:or :;plastic, .may be leancdzandrreusejd. 'i-loweverrthetcleaning:proc- :essnequires :fsponging ;of gthe copy surface with appropriate solvents, and during :sponging the master sheet must be held firmly atwboth 3611115.

;An object of ;'this -;i nven,tion is '--,tc::provide a rack constructedwtot'hold an-iofisetwmaster sheet I duringzspongingzor other'treatment.

.-;A:.iurther object .of (this: inventionzis :to 1 provide a a rack having :cl-amps :adapted zto engage both ends-oi :a master rsheetsto hold the master sheet flateand smooth :during treatment.

A;further.:,obiect:of "this invention isi'xto ,prov-ide a::ra.ck :having :clampin :members --whi ch are. s urged-asatosgrip :the ends :of a :master sheet as pressure iswa-pplied to the surface-:of thewmaster sheet. 7

IA (further cbject: of, this gv-inventiong-is :to provide a mack which egrips :a master ashect with greater :firmness; as the :gpressp-re sapplied 'zto the master sheet .istincreased.

.the use 30f -;photo-sensitizedwmasters, it is necessary to sponge a sensitized surface 'with appropriate photographic:developers; and a further object of this :inventionais sto provide arraok-ior holding a photo-sensitizedfimaster sheet during sponging.

:;'Ihe sends f :master sheeta particuIarly paper master :sheets, :may:beunnecessarily weakened if excessively rwetted with "cleaning --or developing solutions, and-71a ffurther object "of this, invention is to provide :arack i-having :clamps which .completely cover the ends of a master sheet to protect the endsthereofirom cleaning and developing fluids.

The above and other objects and features of the invention will in part be obvious-and will :in part be apparent from the following-detailed dee scription, and th drawing, ,in which:

Figure 1 is a perspective view showing a rack constructed in accordance with an embodiment of this; invention; I

Fig. '2 is'a view in -side elevation showing the rack and a master sheet thereon; and

Fig. 3 is a fragmentary plan view, partly broken 5 Claims. (01.101-131) "2 away and in'section, of an'end of the rack and a master sheet thereon.

In the *following detailed description and'the drawing, like reference characters indicate like parts. i

.-As shown in Figs. -1 and '2 ,the rack includes :aiflat, rectangular main panel 10 which-is'just lailittlewlarger than a master: sheet I 2 which may .be hel'dion'the' rack. The main panel [Dis provided at its ends :With transverse hinges 13 and 4:4 to which are :hi'nged Z- shaped clamping and support members IB and IT. Only'the'clamping andlsupport' fl-memberfli will be described asi the clamping and support members island t! are generally similarin construction.

*The clamping and :support member: l'fiiislgen-e -'er.ally of 'Z-shape :and includes .a lower ..arm' I58 to lWhiCh are attached a rubber support :pa'ds. t9 which .carry the Weight :ofithe vrack and resist downward pressure rm the =main panel H]. A central portioningofithetmember "k6 .is attached to :the :hinge. 'An upper arm :22 :of -zthe member 155 overhangs the ends; ofithe main ,panel .to which the member-is hinged and a lip :23 isadapted to :engage and hold'zthe xend zofithe master: sheet. 'Asshown iniEig. 2, the clamping a-and support member I6 may swing to raise the lip 231mm the "panel 0: for inserting an end of "the-master sheetxlZ. A handle 52:4 attached tothe central portion .of the-clamping E and support ,member :I 6 :may :be used :ior swinging..the member l Sibetween engaged and disengaged position."

- As shown in Fig; 1 the upper arm-1 22 aandvth lip;23.are coeXtensiveuwith the width ofithermain panel 110 isoathat, when :the member 116 {is in engaged position, the arm "22 and the lip s23=form protective ccversjonthe end of thew-masters-sheet. Ase-shown .-iniFig::-3, theends of the master-sheet are provided vwith hook :members 2-6, andthe clamp-:memberprotectszthese hook members during treatmentl'o'f the-:mastersh'eet preventing awetting ,thereof awhile theibody of the *master sheet *is beings'ponged; I I

When'theer'ack is to -:be:used,uthe handle-Mend aesimilar' handlet23l attached tothe clamping 'and support member l may be gripped and the clamping and support members are =turned back away from the imam-panel ii! 5 to the position shown in a, dot 'dash -lines' at tick-Ila, in Fi 2 at which the entire surface or the ma'in panel I 0 isexposed; Thenthemajster sheet'l-Z is placed on the panel' H] and the clamping and support members are swung -inwardly to the"position shown in Fig. l to grip the opposite ends of the master sheet and hold the master sheet flat on top of the panel [0. When the master sheet is so disposed, it may be sponged for cleaning or other treatment, and the greater the pressure exerted upon the top of the master sheet, the greater is the clamping pressure applied to the ends of the master sheet. The upper arm 22 and lip 23 of the clamping and support member [6 and a corresponding upper arm 23 and lip'29 of the member 1'! form protective covers for the ends of the master sheet preventing wetting thereof.

The rack may be readily constructed of sheet metal parts and the like. The clamping and support members l6 and I! are preferably formed'of metal having su-fiicient resiliency or spring to,

cause the clamping and support members to resiliently grip the ends of the master sheet when pressure is applied on panel Ill.

The embodiment of the invention described above and illustrated in the drawing is subject to structural modification without departing from the spirit and scope of the appended claims- Having described my invention What I claim as new and desire to secure by Letters Patent is:

l. A rack for holding an offset master sheet during treatment which comprises a fiat, substantially rectangular panel adapted to support the master sheet, a pair of Z-shaped clamping and support members hinged on opposite ends of the rectangular panel, each of said clamping and support members including a lower'arm extending away from the panel below the panel for supporting the panel, a central portion to which the hinge is attached, an upper clamping arm adapted to overlie the end of the panel to which v the clampingand support member is hinged, and

a lip on the inner edge of the upper arm, the lower arm lying to that side of the hinge remote from the upper arm, the lips of said clamping and support members being adapted to engage and grip the ends of the mastersheet and thereby hold the master sheet on the panel when the lower arms of the clamping and support members support the rack, whereby when pressure is applied on the upper side of the master sheet, the clamping and support members grip the master sheet.

2. The rack in accordance with-claim 1 characterized by the fact that the lip of each clamping and support member is substantially coextensive with the width of the panel to grip an end of the master sheet.

3. A rack for holding an ofiset master sheet during treatment which comprises aflat, substantially rectangular panel adapted to support the master sheet, a pair of Z-shaped clamping and support members hinged on opposite ends of the rectangular panel, each of said clamping and support members including a lower arm extending away from the panel below the panel for supporting the panel, a central portion to which the hinge is attached, an upper clamping arm adapted to overlie the end of the panel to which the clamping and support member is hinged, and a lip on the inner edge of the upper arm, the lower arm lying to that side of the hinge remote from the upper, arm, the lips of said clamping and support members being adapted to engage and grip the ends of the mastersheet and thereby hold the master sheet on the panel when the lower arms of the clamping and support mem- H bers support the rack whereby when pressure is applied on the upper side of themaster sheet, the

lips of each of the clamping and support members grip the master sheet, each of the lips extending substantially across the end of the panel to engage the master sheet throughout the width thereof.

l. A rack for holding an offset master sheet during treatment which comprises a fiat, substantially rectangular panel adapted to support the master sheet, a pair of Z-shaped clamping and support members hinged on opposite ends of the rectangular panel, each of said clamping and support members including a lower arm extending away from the panel below the panel for supporting the panel, a central portion to which the hinge is attached, and an upper clamping arm adapted'to overlie the end of the panel to which the-clamping and support member is hinged, and a lip on the inner edge of the upper arm, the lower arm lying to that side of the hinge remote from he upper arm, the lips of said clamping and support members being adapted to engage and gr" the ends of the master sheet and thereby hold the master sheet on thepanel when the lower arms of the clamping and support members support the rack, whereby when'pressure is applied on the upper side of themaster sheet the lips of each of the clamping and support members grip the master sheet, each lip and each upper arm extending substantially across the'end of the panel so that each lip engages the master sheet throughout the Width'thereof and the lip and the upper arm of each clamping and support member forms a cover over one of the ends of the master sheet to protect the ends of the mastersheet. v

5. A'rack for holding an ofiset master sheet during treatment which comprises a fiat, substantially rectangularpanel adapted to support the master sheet, a pair of Z-shaped clamping and support members hinged on opposite ends of the rectangular panel, each of said clampingand support members including a lower arm extending away from the panel below the panel for supporting the panel, a central portion to which the hinge is attached, and an upper clamping arm adapted to overlie the end of the panel to which the clamping and support member is hinged, and a lip on the inner edge of the upper arm, the lower arm lying to that side of the hinge remote from the upper arm, the lips of said clamping and support members being adapted to engage andgrip the ends of the master sheet and thereby hold the master sheet on the panel when the lower arms of the clamping and support members support the rack, whereby when pressure is applied on the upper side of the master sheet, the clamping and support members grip the master sheet, the clamping and support members being adapted to swing below the panel to a disengaged and panel supporting position in which the clamping and support members are adapted to support the panel with its upper surface exposed.

FRED H. DAVIS.

REFERENCES CITED The following references are of record in the file of-this patent: I

UNITED STATES PATENTS Number Name Date 965,887 Flanigan Aug. 2, 1910 2,103,617 Gericke Dec. 28, 1937 

